Loading, unloading or transferring containers is generally carried out by cranes or other lifting devices, wherein the containers are lifted from the side or from the top, depending on the corresponding standard. Moving containers by cranes, however, is a problem at all railways with overhead wires. For safety reasons, special Diesel mechanical locomotives must be used to move the trains to a loading station wherein moving of the containers can be carried out without the danger of contacting the overhead wires.
This type of loading is time consuming and expensive due to the operating and the maintenance costs of the cranes, the loading stations, the tracks and the locomotives. For this reason, the share of container transport by train is far below the reasonable volume. Technical development has been limited, however, almost exclusively to lifting devices with little attention given to loading and unloading.
Forklift trucks are used if the containers to be moved are out of reach of the cranes. The main drawback in using these trucks is that lifting and lowering can only be carried out on the same side. Further disadvantage is that the containers are lifted rather high which results in the same safety hazard with the overhead wires.
U.S. Pat. No. 3,637,100 discloses a swing shift forklift truck having a lift assembly attached to the side of a single-swing arm. The vehicle is capable of operating either as a front loader or as a side loader but can only be used in storehouses where the loads must be moved in relatively small spaces.
DE 25 21 087 discloses another lift assembly arranged on the container transporting vehicle itself. The lift assembly is rolling on rails mounted on one or both sides of the vehicle during loading or unloading. The assembly as described is clearly not capable of loading or rearranging containers and, moreover, providing all container transporting vehicle with such lift assemblies would result in unrealistic costs.
The apparatus described in the DE AS 1 531 990 is mounted on a vehicle provided with wheels and is used for loading containers. The lift assembly is moving on rails attached to and overreaching the vehicle on both sides. The containers are lifted and lowered between the rails. This apparatus is capable of loading, rearranging and unloading containers, however, the overreaching rails, restrain its use considerably as only single containers can be moved in this way.
As the containers are generally transported in great numbers and are coupled to each other, the use of the apparatus is rather limited.
WO 97/03014 discloses a car for lifting and/or moving containers comprising a base structure with wheels; parallel beams arranged on the base structure; container supports above the beams; carriages rolling on the beams and provided with means for lifting and/or moving containers, said means being foldable below the level of the container supports, wherein said container supports are arranged outside of the path of the carriages. This car can be used for moving containers under overhead wires but is not able to handle all kinds of containers either.